2001 Yz426F questions

hey i got a 2001 yz426f and just want some info on it!!! its got some after market parts like sprocket and exhaust and thats its but i was wondering what parts would benefit it further..... and also when i start it for the first couple minutes its puffs out a little bit of smoke its a light blue!! this good or bad?

Blue/white smoke is burnt oil. That means the piston-rings are worn. If this happens only for a short moment after startup, don't worry too much about it, but if it smokes for longer period, or when you pull hard, than probably you should replace the rings.

If it doesn't have auto-decomp, it should :p (YZ450 or HotCams exhaust cam), I also heard the BK mod is good, will do it myself this month.

Bad rings are not always the only culprit if it only smokes at start up, it could also be bad valve guides too....although this is less likely.

It's actually more likely. In fact, oil smoke on startup that disappears in a minute or two is a classic symptom of leaking valve guide seals. Rings will cause smoke under way and under pressure.

As with any oil consumption issue, keep an eye on your oil level. There's only so much in the engine. And remember to check it only after the bike has been run for a minute or two at least.

I really like the remote hot start and the auto decompression hot cam with YZ timing. But getting it jetted right is key. I think I had a 165main, stock YZ needle, 4th clip, 45 pilot, 1.75 turns out.

Get the thumper racing plug for the decompression linkage. Take your time when you put it in and make sure not to strip the bolt in the head. I have had to helicoil a few.

Get a scotts SS mesh oil filter.

Ride it often, it keeps you sane! :p

Not enough info here to really say for sure either way, of course one would need to investigate the guides and rings...or know the history of this engine.

Usually see rings wear out before valve guides is my point, speaking generally...not this case specifically.

Usually see rings wear out before valve guides is my point, speaking generally...not this case specifically.

True, especially with a bucket tappet engine, and especially with a YZF. However, valve guide wear is not the issue, only the condition of the seals.

thanks to all it only smokes for a couple minutes when i start it up and its fine after that and does smoke while riding...

I highly recommend the moose racing air/fuel screw made by zip ty. This is something every bike should have.

If it does smoke when you're riding (blue/white) than the engine is worn, at least rings should be replaced. Does it consume oil? Check your oil level before/after rides, it should not drop.

If or how much it may smoke while riding will also depend on the oil viscosity, engine temp etc. If its smoking some while riding, One cheaper and easier way (rather then tearing down the motor) to at least see if the rings are the main source of oil burning...if your are running 30 or 40 weight oil, try 50w oil. At least this could give you a better idea, but valve guide seals can't be ruled out either regardless.

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